Several breeding blanket concepts for the DEMO reactor employ the eutectic Pb–16Li as breeder material, namely Helium Cooled Lithium Lead (HCLL), Water Cooled Lithium Lead (WCLL) and Dual Coolant Lithium Lead (DCLL). These three concepts share, with different incidences, three major technological challenges: Tritium containment, steel corrosion and magnetohydrodynamic drag. Here, we describe the ongoing work on multifunctional Al2O3 nanoceramic coatings grown by Pulsed Laser Deposition (PLD) on Reduction-Activation Ferritic-Martensitic (RAFM) steel. In fact, PLD can produce relatively thick (up to tens of μm) high performance coatings with metal-like mechanical properties. The coatings were tested as Tritium permeation barriers with Hydrogen at different temperature (from 350 to 650 °C). Results collected in this way indicate an excellent behavior, with a permeation reduction factor (PRF) close to 105. In addition, it was shown that they are able to maintain similar properties even when Deuterium was employed and also under 2 MeVelectrons irradiation.  Moreover, the electrical conductivity of these dielectric coatings was shown to be extremely low even under irradiation. Finally, to evaluate the chemical compatibility of Al2O3 films in liquid eutectic Pb-16Li, PLD deposited samples have been exposed to static corrosion tests up to 8000 h. No corrosive attacks of the steel substrate are detected. To conclude, Alumina coatings deposited by PLD show optimal characteristics in order to tackle the major technological challenges associated to the Breeding Blanket (BB) concepts employing Pb-16Li as breeder materials.
|Titolo:||Multifunctional nanoceramic coatings for future generation nuclear systems|
|Data di pubblicazione:||2019|
|Appare nelle tipologie:||1.1 Articolo in rivista|